Guarantor/Non Guarantor Condensed Consolidated Financial Statements (Balance Sheet (Unaudited)) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 35,679	$ 34,924	$ 26,439	$ 27,385
Receivables, net of allowance	81,973	190,201
Intercompany receivable (payable)	0	0
Deferred income taxes	6,299	10,998
Inventory	8,995	14,117
Assets held for sale	2,065	9,909
Prepaid expenses and other current assets	5,927	8,925
Total current assets	140,938	269,074
Net property and equipment	778,696	856,541
Investments in subsidiaries	0	0
Intangible assets, net of accumulated amortization	18,268	24,223
Noncurrent deferred income taxes	0	2,753
Other long-term assets	11,226	18,998
Total assets	949,128	1,171,589	1,264,757
Current liabilities:
Accounts payable	35,072	64,305
Current portion of long-term debt	0	27
Deferred revenues	14,772	3,315
Accrued expenses	47,463	79,545
Total current liabilities	97,307	147,192
Long-term debt, less current portion	410,000	455,053
Noncurrent deferred income taxes	48,745	69,578
Other long-term liabilities	4,193	4,702
Total liabilities	560,245	676,525
Total shareholders' equity	388,883	495,064
Total liabilities and shareholders' equity	949,128	1,171,589
Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	1,770	(5,516)	(3,123)	(2,059)
Receivables, net of allowance	68,008	151,048
Intercompany receivable (payable)	34,169	55,567
Deferred income taxes	5,472	8,196
Inventory	5,841	7,208
Assets held for sale	2,065	9,909
Prepaid expenses and other current assets	3,052	6,554
Total current assets	120,377	232,966
Net property and equipment	741,288	763,994
Investments in subsidiaries	43,254	116,799
Intangible assets, net of accumulated amortization	18,268	24,223
Noncurrent deferred income taxes	0	0
Other long-term assets	919	1,955
Total assets	924,106	1,139,937
Current liabilities:
Accounts payable	32,562	57,910
Current portion of long-term debt		27
Deferred revenues	13,993	3,315
Accrued expenses	41,042	64,063
Total current liabilities	87,597	125,315
Long-term debt, less current portion	0	53
Noncurrent deferred income taxes	127,409	160,104
Other long-term liabilities	2,994	3,658
Total liabilities	218,000	289,130
Total shareholders' equity	706,106	850,807
Total liabilities and shareholders' equity	924,106	1,139,937
Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	7,560	12,752	10,435	1,076
Receivables, net of allowance	11,655	37,512
Intercompany receivable (payable)	(9,333)	(30,728)
Deferred income taxes	76	975
Inventory	3,154	6,909
Assets held for sale	0	0
Prepaid expenses and other current assets	1,566	1,154
Total current assets	14,678	28,574
Net property and equipment	33,933	89,118
Investments in subsidiaries	0	0
Intangible assets, net of accumulated amortization	0	0
Noncurrent deferred income taxes	0	2,753
Other long-term assets	777	6,921
Total assets	49,388	127,366
Current liabilities:
Accounts payable	1,928	5,660
Current portion of long-term debt		0
Deferred revenues	779	0
Accrued expenses	2,792	4,376
Total current liabilities	5,499	10,036
Long-term debt, less current portion	0	0
Noncurrent deferred income taxes	0	0
Other long-term liabilities	635	531
Total liabilities	6,134	10,567
Total shareholders' equity	43,254	116,799
Total liabilities and shareholders' equity	49,388	127,366
Eliminations [Member]
Current assets:
Cash and cash equivalents	0	0
Receivables, net of allowance	0	0
Intercompany receivable (payable)	0	(3)
Deferred income taxes	0	0
Inventory	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	(3)
Net property and equipment	0	(750)
Investments in subsidiaries	(749,360)	(967,606)
Intangible assets, net of accumulated amortization	0	0
Noncurrent deferred income taxes	(78,664)	(90,664)
Other long-term assets	0	0
Total assets	(828,024)	(1,059,023)
Current liabilities:
Accounts payable	0	0
Current portion of long-term debt		0
Deferred revenues	0	0
Accrued expenses	0	(3)
Total current liabilities	0	(3)
Long-term debt, less current portion	0	0
Noncurrent deferred income taxes	(78,664)	(90,664)
Other long-term liabilities	0	0
Total liabilities	(78,664)	(90,667)
Total shareholders' equity	(749,360)	(968,356)
Total liabilities and shareholders' equity	(828,024)	(1,059,023)
Parent [Member]
Current assets:
Cash and cash equivalents	26,349	27,688	$ 19,127	$ 28,368
Receivables, net of allowance	2,310	1,641
Intercompany receivable (payable)	(24,836)	(24,836)
Deferred income taxes	751	1,827
Inventory	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	1,309	1,217
Total current assets	5,883	7,537
Net property and equipment	3,475	4,179
Investments in subsidiaries	706,106	850,807
Intangible assets, net of accumulated amortization	0	0
Noncurrent deferred income taxes	78,664	90,664
Other long-term assets	9,530	10,122
Total assets	803,658	963,309
Current liabilities:
Accounts payable	582	735
Current portion of long-term debt		0
Deferred revenues	0	0
Accrued expenses	3,629	11,109
Total current liabilities	4,211	11,844
Long-term debt, less current portion	410,000	455,000
Noncurrent deferred income taxes	0	138
Other long-term liabilities	564	513
Total liabilities	414,775	467,495
Total shareholders' equity	388,883	495,814
Total liabilities and shareholders' equity	$ 803,658	$ 963,309